Quantum bath suppression in a superconducting circuit by immersion cooling

Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at T ≈ 50 mK - far above the refrigerator base temperature. This is for example reflected in the thermal state population of qubits, in excess numbers of quasiparticles, and polarisation of surface spins - factors contributing to reduced coherence. We demonstrate how to remove this thermal constraint by operating a circuit immersed in liquid ³He. This allows to efficiently cool the decohering environment of a superconducting resonator, and we see a continuous change in measured physical quantities down to previously unexplored sub-mK temperatures. The ³He acts as a heat sink which increases the energy relaxation rate of the quantum bath coupled to the circuit a thousand times, yet the suppressed bath does not introduce additional circuit losses or noise. Such quantum bath suppression can reduce decoherence in quantum circuits and opens a route for both thermal and coherence management in quantum processors.

Spin-Echo Silencing Using a Current-Biased Frequency-Tunable Resonator

The ability to control microwave emission from a spin ensemble is a requirement of several quantum memory protocols. Here, we demonstrate such ability by using a resonator whose frequency can be rapidly tuned with a bias current. We store excitations in an ensemble of rare-earth ions and suppress on demand the echo emission ("echo silencing") by two methods: (1) detuning the resonator during the spin rephasing, and (2) subjecting spins to magnetic field gradients generated by the bias current itself. We also show that spin coherence is preserved during silencing.

[The measurement of degree of satisfaction of patients at evaluation of quality of applied services in hospital on the basis of SERVQUAL technique]

This article discusses clauses of national standards compatible with international standards of ISO 9000-9001 family,in section of measurement of degree of satisfaction of patients with medical services quality. The main methods applied are sociological survey SERVQUAL focused on measurement of degree of satisfaction of patients, GAP-analysis (identification of discrepancies and gaps) and technique of management decision-making concerning improvement of medical services quality. The SERVQUAL survey with its five qualitative criteria was applied. The primary data was obtained from sampling of 500 well structured questionnaires. In total, 365 respondents participated in the study. The produced correlation matrix confirmed strong relations between criteria estimating expected and interpreted quality of medical services and full average interpreted quality. The analysis of reliability confirmed that questions of questionnaire are reliable and the results of statistical calculations can be used in further analysis. The analysis of descriptive statistics, correlation matrix, patient profile, reliability and qualitative GAP analysis were carried out. The requirements of assuring reliability and adequacy of questionnaire, representativeness of sample size to carry out high quality measurements were kept. The results on every criterion were obtained. The qualitative results of discrepancy of and perceptions of patients are received. The negative values of indices of discrepancy of the interpreted and expected outcomes of medical services are received. The level of satisfaction of patients remains insufficient. The study proposes to improve quality of medical services in hospital, especially by criterion "Materiality" to justify expectations of patients. The results of the study are of practical importance for executives of regional health care administrations, head physicians of medical organizations engaged in improvement of medical care quality and increasing of efficiency of medical services.

[The experience of SERVQUAL technique application in measuring satisfaction of patients with medical services quality]

The implementation of system of quality control conforming to requirements of interstate ISO 9001 standards in in the medical organization, the important role is assigned to indicator of satisfaction of patients with quality of medical care as a feedback channel. The study purpose was to investigate satisfaction of patients with quality of medical services in medical organization rendering hospital medical care on the basis of SERVQUAL technique. The analysis of results of survey of 339 patients treated in the twenty-four-hour department of municipal hospital demonstrated rather high rating of perception of quality of rendered medical services that made up to 4.47 points according five-point scale. The application of GAP analysis technique allowed to reveal gaps between expected and real quality of received medical services by means of SQL index quality. The highest points were received for such criteria as "Sympathy" (0.61 points), "Responsiveness" (0.20 points). The satisfactory results were in case of criteria "Materiality" (-0.38 points), "Reliability (-0.43 points). The lowest points were received for criteria "Persuasiveness, confidence" (-0.69 points) that reflects inadequate orientation of hospital personnel to settle problems of patients. The study demonstrated that applying the SERVQUAL technique in assessment of quality of medical services allows to reveal the most significant factors determining satisfaction of patients. The results of survey based on the SERVQUAL technique and processed by GAP analysis are to be considered in management decision making concerning choice of correcting and preventive actions in quality management of rendering medical services at the regional level.

Two-level systems in superconducting quantum devices due to trapped quasiparticles

A major issue for the implementation of large-scale superconducting quantum circuits is the interaction with interfacial two-level system (TLS) defects that lead to qubit parameter fluctuations and relaxation. Another major challenge comes from nonequilibrium quasiparticles (QPs) that result in qubit relaxation and dephasing. Here, we reveal a previously unexplored decoherence mechanism in the form of a new type of TLS originating from trapped QPs, which can induce qubit relaxation. Using spectral, temporal, thermal, and magnetic field mapping of TLS-induced fluctuations in frequency tunable resonators, we identify a highly coherent subset of the general TLS population with a low reconfiguration temperature ∼300 mK and a nonuniform density of states. These properties can be understood if the TLS are formed by QPs trapped in shallow subgap states formed by spatial fluctutations of the superconducting order parameter. This implies that even very rare QP bursts will affect coherence over exponentially long time scales.

Near-Field Scanning Microwave Microscopy in the Single Photon Regime

The microwave properties of nano-scale structures are important in a wide variety of applications in quantum technology. Here we describe a low-power cryogenic near-field scanning microwave microscope (NSMM) which maintains nano-scale dielectric contrast down to the single microwave photon regime, up to 109 times lower power than in typical NSMMs. We discuss the remaining challenges towards developing nano-scale NSMM for quantum coherent interaction with two-level systems as an enabling tool for the development of quantum technologies in the microwave regime.

Direct Identification of Dilute Surface Spins on Al_{2}O_{3}: Origin of Flux Noise in Quantum Circuits

An on-chip electron spin resonance technique is applied to reveal the nature and origin of surface spins on Al_{2}O_{3}. We measure a spin density of 2.2×10^{17}  spins/m^{2}, attributed to physisorbed atomic hydrogen and S=1/2 electron spin states on the surface. This is direct evidence for the nature of spins responsible for flux noise in quantum circuits, which has been an issue of interest for several decades. Our findings open up a new approach to the identification and controlled reduction of paramagnetic sources of noise and decoherence in superconducting quantum devices.

Coherent interaction with two-level fluctuators using near field scanning microwave microscopy

Near field Scanning Microwave Microscopy (NSMM) is a scanning probe technique that non-invasively can obtain material properties on the nano-scale at microwave frequencies. While focus has been on developing room-temperature systems it was recently shown that this technique can potentially reach the quantum regime, opening up for applications in materials science and device characterization in solid state quantum information processing. In this paper we theoretically investigate this new regime of NSMM. Specifically we show that interaction between a resonant NSMM probe and certain types of two-level systems become possible when the NSMM probe operates in the (sub-) single photon regime, and we expect a high signal-to-noise ratio if operated under the right conditions. This would allow to detect single atomic material defects with energy splittings in the GHz range with nano-scale resolution, provided that individual defects in the material under study are well enough separated. We estimate that this condition is fulfilled for materials with loss tangents below tan δ ∼ 10(-3) which holds for materials used in today's quantum circuits and devices where typically tan δ < 10(-5). We also propose several extensions to a resonant NSMM that could improve sensitivity and functionality also for microscopes operating in a high power regime.

Targeting neddylation induces DNA damage and checkpoint activation and sensitizes chronic lymphocytic leukemia B cells to alkylating agents

Microenvironment-mediated upregulation of the B-cell receptor (BCR) and nuclear factor-κB (NF-κB) signaling in CLL cells resident in the lymph node and bone marrow promotes apoptosis evasion and clonal expansion. We recently reported that MLN4924 (pevonedistat), an investigational agent that inhibits the NEDD8-activating enzyme (NAE), abrogates stromal-mediated NF-κB pathway activity and CLL cell survival. However, the NAE pathway also assists degradation of multiple other substrates. MLN4924 has been shown to induce DNA damage and cell cycle arrest, but the importance of this mechanism in primary neoplastic B cells has not been studied. Here we mimicked the lymph node microenvironment using CD40 ligand (CD40L)-expressing stroma and interleukin-21 (IL-21) to find that inducing proliferation of the primary CLL cells conferred enhanced sensitivity to NAE inhibition. Treatment of the CD40-stimulated CLL cells with MLN4924 resulted in deregulation of Cdt1, a DNA replication licensing factor, and cell cycle inhibitors p21 and p27. This led to DNA damage, checkpoint activation and G2 arrest. Alkylating agents bendamustine and chlorambucil enhanced MLN4924-mediated DNA damage and apoptosis. These events were more prominent in cells stimulated with IL-21 compared with CD40L alone, indicating that, following NAE inhibition, the culture conditions were able to direct CLL cell fate from an NF-κB inhibition to a Cdt1 induction program. Our data provide insight into the biological consequences of targeting NAE in CLL and serves as further rationale for studying the clinical activity of MLN4924 in CLL, particularly in combination with alkylating agents.

[Working conditions and morbidity rate in employers at the South-East railway transport]

In the article there are presented the results of the examination of working conditions atfactories of the South-Eastern Railway, which has lost its effectiveness due to the action of certain laws. The situation on labor conditions was shown to be not entirely safe. There is given an analysis of the morbidity due to the temporary disability and occupational disease rates in foot-plate staff workers. There was made an emphasis on working conditions and morbidity rate in foot-plate staff workers. There is posed a question about the inclusion of essential hypertension in foot-plate staff workers in the list of occupational diseases.

Charge qubit coupled to an intense microwave electromagnetic field in a superconducting Nb device: evidence for photon-assisted quasiparticle tunneling

We study a superconducting charge qubit coupled to an intensive electromagnetic field and probe changes in the resonance frequency of the formed dressed states. At large driving strengths, exceeding the qubit energy-level splitting, this reveals the well known Landau-Zener-Stückelberg interference structure of a longitudinally driven two-level system. For even stronger drives, we observe a significant change in the Landau-Zener-Stückelberg pattern and contrast. We attribute this to photon-assisted quasiparticle tunneling in the qubit. This results in the recovery of the qubit parity, eliminating effects of quasiparticle poisoning, and leads to an enhanced interferometric response. The interference pattern becomes robust to quasiparticle poisoning and has a good potential for accurate charge sensing.

A near-field scanning microwave microscope based on a superconducting resonator for low power measurements

We report on the design and performance of a cryogenic (300 mK) near-field scanning microwave microscope. It uses a microwave resonator as the near-field sensor, operating at a frequency of 6 GHz and microwave probing amplitudes down to 100 μV, approaching low enough photon population (N ∼ 1000) of the resonator such that coherent quantum manipulation becomes feasible. The resonator is made out of a miniaturized distributed fractal superconducting circuit that is integrated with the probing tip, micromachined to be compact enough such that it can be mounted directly on a quartz tuning-fork, and used for parallel operation as an atomic force microscope (AFM). The resonator is magnetically coupled to a transmission line for readout, and to achieve enhanced sensitivity we employ a Pound-Drever-Hall measurement scheme to lock to the resonance frequency. We achieve a well localized near-field around the tip such that the microwave resolution is comparable to the AFM resolution, and a capacitive sensitivity down to 6.4 × 10(-20) F/Hz, limited by mechanical noise. We believe that the results presented here are a significant step towards probing quantum systems at the nanoscale using near-field scanning microwave microscopy.

Size exclusion chromatography on soft and semi-rigid packing materials in the dynamic axial compression mode

The effect of dynamic axial compression within a range of up to 5 bar upon the structure of the bed packed with soft and semi-rigid packing materials (Sephadex G-25, Bio-Gel P2 and Toyopearl HW-40) and the associated chromatographic parameters were studied for size exclusion chromatography. Continuous packing compression is accomplished by use of a special column with controlled external pressure applied to the packing. Compression has been shown to favor an overall increase in the resolution with pressure optima observed in some cases.

[Effect of lactoferrin on the development of acute and chronic adjuvant arthritis]

An experiment revealed that the therapeutic administration of lactoferrin exerted no effect on the development of early stages of adjuvant arthritis in albino rats during chronicity. This was accompanied by decreased complement consumption and by the lower blood activity of polymorphonuclear leukocytes. The authors consider that this effect is associated with the capacity of lactoferrin to inhibit the excessive proinflammatory activity of neutrophilic leukocytes, which is characteristic of the chronicity of inflammation.

[Correcting effect of the locus coeruleus on ophthalmic hypertension of the hypothalamic genesis]

We studied the intraocular pressure and the humor aquosus volume changes after a chronic emotional stress produced by a prolonged electrical stimulation of the multiple ventromedial (VMHN) hypothalamic nuclei and the locus coeruleus. The VMHN stimulation caused an increase in the intraocular pressure and production of the humor aquosus, as well as a decrease in the outflow ratio. Stimulation of the locus coeruleus increased the intraocular pressure to a lesser extent. A combined effect of both types of stimulation normalised the intraocular pressure due to a decrease in the humor aquosus production, the outflow ratio remaining unchanged.

[On ranges of the malaria mosquitoes (Diptera: Culicidae: Anopheles) of the Maculipennis complex on the territory of Russia]

Maps and distribution data are provided for the seven mosquito species of the genus Anopheles, the maculipennis group: Anopheles atroparvus, A. beklemishevi, A. maculipennis, A. messeae, A. malanoon, A. sacharovi and A. subalpinus.

[Distribution ranges of malarial mosquitoes other than Anopheles maculipennis species (Diptera, Culicidae) in Russia]

Maps and distribution data for six species of the genus Anopheles in Russia are given.

Spontaneous shape distortion in quench-condensed bismuth clusters below 8 K

We study single-electron transport in quench-condensed bismuth films. By lateral confinement, we select a specific cluster of about 10(3) atoms and use tunneling barriers that appear naturally during thin-film formation. A remarkable reversible increase of the sample conductance up to 5 times was found as the temperature was lowered from 11 to 4 K. We attribute this effect to a spontaneous distortion of the cluster shape and discuss its relation to a phase transition predicted for free metallic clusters.

[A system of individual immunotherapy with leakadin in the combined therapy of acoustic neurinomas]

Analyzing the immunological responsiveness of patients with acoustic neurinomas on the antitumor immunomodulator leacadin has revealed some significant features. In leacadin-treated patients, postimmunotherapy promotes the formation of high sanogenetic responses: an increase in the rigidity of the brain-immune system; elevations of the levels of antitumor factors of the immune system: T helper cells and locally synthesized antibodies; a decrease in neuro-sensitization after tumor removal, which prevents tumor stimulation and recurrence; an indirect reduction in the activity of T suppressors that inhibit immunological responses in growing neoplasm. Immunotherapy with the antitumor immunomodulator leacadin in patients with acoustic neurinomas contributes to the development and optimization of the tumor carrier's immunological adaptative responses, creates conditions for the optimal postoperative course and prevents recurrence.

[The automated "SynChrom" system for solid-phase synthesis of peptides and liquid column chromatography. I. Principles of design and structural constituents]

An automatic modular SynChrom system was designed for solid phase synthesis and chromatographic purification of peptides. Structural constituents and organization and operation of the system in solid phase peptide synthesis and liquid column chromatography modes are described. Swellographic monitoring of the course of synthesis was used. Hydraulic diagrams, operation algorithm and software description are presented.

[The automated "SynChrom" system for solid-phase synthesis of peptides and liquid column chromatography. II. Use in the solid-phase synthesis of peptides and liquid column chromatography]

Automatic solid phase peptide synthesis using the SynChrom system is described. Problems of swellographic monitoring are discussed. Combined monitoring (swellographic, spectrophotometric, and manometric) of all steps of the synthetic cycle are suggested. Potential applications of the system to liquid column chromatography were demonstrated.

[Surface localization of amino acids in influenza virus hemagglutinin during functional transformation of virions by acidic pH]

Tritium planigraphy method was used to study the surface amino acids in influenza virus hemagglutinin (HA) at the functional transformation of virions by acidic pH. Influenza viruses undergo this transformation when virions penetrate a target cell. The mild bombardment of a whole virion by hot tritium atoms labels the surface-exposed HA amino acids without disturbing virion structure and infectivity. A comparison of the values of specific radioactivity of the HA subunits (HA1 and HA2) and analysis of the label distribution in individual amino acids in control (pH 7.4) and experimental (pH 5.0) viral samples has shown that: (i) The accessibility of a hemagglutinin molecule for tritium labeling is decreased at acidic pH; (ii) Compactization of apical HA1 hemagglutinin subunit increases at acidic pH; (iii) The HA1 compactization increases the exposition of the basal HA2 hemagglutinin subunit; (iv) The fusion peptide of the HA2 subunit (the N-terminal part) is not accessible for tritium label after the acidic exposition of virions. These data are in an agreement with the hypothesis that hemagglutinin fusion peptide is exposed only while contacting the target cell membrane at acidic pH.

[Optimization of a protocol for automatic solid phase synthesis of peptides using a variable volume flow reactor]

The protocol for solid phase peptide synthesis using automatic synthesizers MilliGen/Biosearch 9500 and 9600 with built-in variable volume flow-reactors has been elaborated. The data of swellographic monitoring were used for optimization of process parameters. The peptides involving from 10 to 21 amino acid residues were synthesized using developed protocol. Significant economy of reagents and solvents has been demonstrated for synthesis of good quality peptides.

[Analysis of the trypsin hydrolysate of a 40-kDa protein, found in the nucleoprotein of serum. Identification of it as alpha(1)-acidic glycoprotein (orosomucoid)]

From the tryptic hydrolysis of 40-kDa protein from the mouse blood serum thirty-four peptides were isolated by HPLC, of which complete and partial amino acid sequence was established for twenty-eight and six, respectively. On the basis of these data the protein is identified as the blood serum alpha 1-acid glycoprotein.

Flexible endoscopes. Ophthalmoendoscopic techniques and case reports

We successfully used three types of flexible ophthalmoendoscopes for the surgical treatment of various abnormalities in the posterior ocular segments. All 23 patients had opacification of the cornea and lens, which made it difficult or even impossible to perform intravitreal surgery on the "closed" eye. All operations were performed through the pars plana. No complications were noted.

Flexible endoscope for intraocular surgery

We describe the technical characteristics of three types of flexible ophthalmoendoscopes used for direct visual examination and for taking photographs of intraocular structures. The designs of these instruments can be used as a basis for the development of new models of thin ophthalmoendoscopes.

[Use of thrombin in the prevention and arrest of intraocular hemorrhage during vitrectomy in traumatic hemophthalmos]

Thrombin obtained from donor blood plasma was used to achieve hemostasis during vitrectomy for traumatic hemophthalmos. Analysis of the results of surgery in 21 patients and in 28 controls has shown a manifest hemostatic activity of the agent. If introduced intravitreally, it induced no local reaction of tissues. Thrombin is recommended for clinical application.

[Possibilities of the use of rigid and flexible ophthalmoendoscopes in the diagnosis and treatment of intraocular pathology]

The authors analyse the potentialities of the rigid and flexible fiber optics-based ophthalmoendoscopes, made in this country, in the diagnosis and treatment of impairments and diseases of the eyeball. The endoscopes have been employed during intraocular interventions in 18 patients with various abnormalities of the posterior segment of the eye. Comparison of the rigid (MD-71M) and flexible (OGE-1) endoscopes has shown the advantages of the latter design for intraocular surgery. Prospects in the use of ophthalmoendoscopy are outlined. The authors emphasize the possibility of surgery on a 'closed eye' with the use of a flexible endoscope in cases when the transparency of the anterior optic media is essentially reduced or absent; this limits the need in traumatic surgical interventions like the 'open sky'.